low tech. Co2 and surface agitation.

baron von bubba

Junior Poster
Mar 15, 2009
hi all,
Planning a new low tech.
I'm aware fish and bacteria supply a certain amount of co2, but is it significant enough to prohibit the use of surface agitation?

Basically is it agitation to increase and maintain O2?
Or no agitation to keep the extra co2 thats produced in the tank?



Lifetime Charter Member
Lifetime Member
Mar 12, 2009
What I'm about to say is pretty much heresy in the minds of a lot of people.

I run an airstone on my low tech tanks, and algae isn't a problem so long as the lighting stays low. The concept is that the atmospheric levels of CO2 will create a constant within the tank, rather than risking fluctuations every time the water is changed, the flow dinamics are altered through evaporation, or plants stop photosynthesizing for the day. By maintaining this constant I am likely either providing more CO2 through air than fish can through respiration (more likely than you'd think; they're cold blooded) or I'm maintaining relatively stable CO2 levels at limiting amounts.

Either way, tanks run like this grow slowly and encounter a minimum of algae problems. I tend to use it on tanks with stock lighting around the 1wpg level. So far I've been able to keep H difformis, L. repens and R. rotundifolia this way, along with the usual assortment of anubias, java fern, crypts and mosses. Don't ask about the rotala though; it's currently working on turning into a carpet along the bottom of the tank.